belcher shot and killed his 22-year-old girlfriend, k kasandra perkins, the mother of his 3-month-old daughter at their home. he got in his car, drove to the team's practice facility outside arrowhead stadium where authorities say he thanked the coaches for believing in him. moments later he walked away, shooting himself in the head as cornell and the team's general manager looked on in horror. police are still trying to figure out what caused belcher to snap. he and his girlfriend were reportedly arguing after she returned late from a concert. >> it was an individual that did something that he snapped. and -- and that i don't understand. and i probably never will. >> reporter: it's the latest in a string of player suicides. earlier this year, former falcons safety, ray easterling took his life with a gun, so did o.j. murdock. in may, junior seau died after shooting himself in the chest. the family is having his brain studied. they want to know if the suicide was associated to a history of concussion-related injuries. but the chiefs' management says belcher had no history of head inju